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the check [test] of the system, but the loss of safety function is detected by the check. By comparison, in a system designed to EN ISO
13849-1 Category 4, a single fault or an accumulation of faults will not lead to a loss of the safety function.
While EN ISO 13849-1 generally applies to the machine level, IEC61496-1/-2 specifies requirements for the design, construction and
testing for two levels or "types" of active opto-electronic protective devices (AOPDs) or light curtains (light screens). "Type 2" and "Type
4" describe differing requirements to ensure that appropriate safety-related performance is achieved. The appropriate type is
dependent on the overall degree of risk reduction, as determined by the machine's Risk Assessment (see ISO 12100, ANSI B11.19, or
other relevant standard).
A Type 2 AOPD relies on periodic testing to detect a failure to danger. Between tests, a single fault can result in the loss of the safety
function. While this level of performance and fault tolerance is generally not allowed in Category 4 situations, it is acceptable in the
lower-risk situations described by Category 2.
While the EZ-SCREEN Type 2 conducts continual internal self-tests and all single faults have been considered, the installation should
provide an additional periodic test/check of the EZ-SCREEN Type 2 and its interface to ensure the integrity of the safety function (see
Manual Reset/Remote Test Input and EDM
signal to be sent to the guarded machine and put the System into a Lockout condition.
Recovery from this type of Lockout condition requires:
•
Replacement of the failed component (to restore the safety function)
•
The appropriate reset procedure.
2.5 Operating Features
The Banner EZ-SCREEN Type 2 Light Screen models described by this manual feature standard functions:
•
Trip or Latch Output (depending on model)
•
External Device Monitoring (EDM) via the Test/Retest input
The System Response Time (Tr) can be determined by the model number on the emitter and receiver.
2.5.1 Trip/Latch Output
Whether a receiver features Trip or Latch Output determines whether the System will enter RUN mode automatically after power-up, or
if it will require a manual reset first. If the System has Trip Output, other measures must be taken to prevent a pass-through hazard.
For Latch Output models, the EZ-SCREEN Type 2 requires a manual reset for the OSSD outputs to turn ON, after power is applied and all
beams are clear.
•
For Trip Output models, the OSSD outputs will turn ON after power is applied and the receiver passes its internal self-test/
synchronization and recognizes that all beams are clear. Trip Output models will also turn on after all beams are cleared
following a blocked beam.
•
For Latch Output models, the EZ-SCREEN Type 2 requires a manual reset for the OSSD outputs to turn ON, whenever power is
applied and all beams are clear.
WARNING: Use of Trip/Latch Output
Application of power to the Banner device, the clearing of the defined area, or the reset of a Latch condition MUST
NOT initiate dangerous machine motion. Machine control circuitry must be designed so that one or more initiation
devices must be engaged (in a conscious act) to start the machine – in addition to the Banner device going into
Run mode. Failure to follow these instructions may result in serious bodily injury or death.
2.5.2 Wiring Options for Emitter/Receiver Swapability
Each EZ-SCREEN Type 2 sensor can be connected to its own power supply or, color-for-color to the other sensor's cable. The color-for-
color hookup allows the emitter and receiver positions to be interchanged without rewiring (functionality known as sensor "
swapability"). Model CSB.. splitter cordsets and DEE2R.. double-ended cables facilitate interconnection between an EZ-SCREEN Type 2
receiver and emitter, providing a single "homerun" cable for optional swapable hookup.
on page 31). A component failure detected by periodic test/check must cause a "stop"
www.bannerengineering.com - Tel: 763.544.3164
®
EZ-SCREEN
Type 2 Light Screen
9
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